In communications networks, there may be a challenge to obtain good performance and capacity for a given communications protocol, its parameters and the physical environment in which the communications network is deployed.
For example, wireless networks suffer from issues of having a limited range and unreliable communications. This may cause data sometimes to be received corrupted at the receiver end. As a means to mitigate the range limitations, wireless mesh networks have been developed. In wireless mesh networks network devices acting as intermediary relay nodes relay data from the source to the destination and hence extends the range of the network devices in the wireless mesh network.
Connectivity of a wireless mesh network describes the ratio with which network devices can reach another network devices or network node in a network. In the case of a fully connected network all network devices and network nodes are able to reach all other network devices and network nodes.
Commonly, machine type communication (MTC) in sensor or meter networks is performed towards a single recipient. This single recipient may typically be a server configured to receive sensor or metering data. As a consequence, the only relevant connection, on an applications level, for a network device in such a network is with the server configured to receive data from the network device. In this case the network is thus fully connected if all network devices can communicate with said server. For such a network, a proactive routing mechanism, in which paths are maintained by periodic signaling, is suitable since only one route (i.e., the route to the server) needs to be maintained for all network devices. Hence, if a network device is able to find another network device operatively connected to the server it may itself connect to the server through that network device.
For e.g., the metering application, a rational mesh organization is related to the cost of connecting to the mesh gateway in order to reach the server. A network device closer, e.g., fewer relays and/or better channel conditions, to the gateway can be said to have a good metric. Correspondingly, a network device farther away, e.g., more relays and/or worse channel conditions is said to have a bad metric. A network device linked to a network device having a better metric than itself is a child to said network device, whereas it is a parent to a network device linked to itself having a worse metric than itself.
Wireless mesh networks may be dynamic in the sense that individual network devices may move within the wireless mesh network. However the wireless mesh network itself is usually static in the sense that it covers a relatively fixed geographical area e.g., by means of network nodes acting as access points. A network device that for some reason is detached from the network is then unable to communicate.
Wireless mesh networks are becoming more and more common to be as sensor or meter networks e.g., for electricity or water meters, or for containers loaded on a ship or a shipyard. Such networks are required to be fully connected i.e., all network devices in the network must be able to connect either directly or through at least one other network device to the facilitating server. Some of the network devices in such a network will only be able to connect to the server through a single relay node making that network device entirely dependent on said relay node. In the event of such a relay node dropping out of the network, e.g., due to battery outage or the relay node being moved, the network device becomes detached and will no longer be able to connect to the server through the particular relay node.
Hence, there is a need for improved mechanisms for reconfiguration in a wireless mesh network.